SOLUTION: 36 gallons of 25% alchol solution means : 25%, or one quarter, of the solution is pure alchol. one quarter of 36 is 9. That solution contains 9 gallons of pure alchol. how man

Question 119685: 36 gallons of 25% alchol solution means : 25%, or one quarter, of the solution is pure alchol. one quarter of 36 is 9. That solution contains 9 gallons of pure alchol.

how many gallons of 30% alchol solution and how many of 60% alchol solution must be mixed to produce 18 gallons of 50% solution
Found 2 solutions by stanbon, josmiceli:
Answer by stanbon(75887) (Show Source): You can put this solution on YOUR website!
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how many gallons of 30% alchol solution and how many of 60% alchol solution must be mixed to produce 18 gallons of 50% solution
Let "x" be the amount of 30% alcohol; active ingredient = 0.3x gallons
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Then "18-x" is amt. of 60% alcohol ; act. ingre. =0.6(18-x)=10.8-0.6x gals.
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Amt. of mixture is 18 gals; act. ingre. = 0.5*18 = 9 gallons
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EQUATION:
active = active = active
0.3x + 10.8-0.6x = 9
-0.3x = -1
x = 10/3 = 3 1/3 gallons (Amount of 30% alcohol needed for the mixture.)
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Cheers,
Stan H.

Answer by josmiceli(19441) (Show Source): You can put this solution on YOUR website!
x = number of gallons of 30% alcohol solution
y = number of gallons of 60% alcohol solution
In words:
(alcohol contained in x + alcohol contained in y) / 18 = 50%

and, of course,

In the 1st eqaution,

divide both sides by

Now subtract the bottom equation from the top

6 gallons of the 30% solution must be mixed
with 12 gallons of the 60% solution
check answer:

OK
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